thompson



(No Model.)

E.P. THOMPSON.

METHOD OF EVAOUATING INCANDESGENT ELECTRIC LAMPS. No. 370,997. Patented Oct. 4,1887;

Genera/0 UNITED STATES PATENT OFFICE.

EDWARD P. THOMPSON, OF ELIZABETH, NEW JERSEY.

METHOD OF EVACUATING INCANDESCENT ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 370,997, dated October 4, 1887.

Application filed January 22, 1887. Serial No. 225,116.

To aZZ whom it may concern:

Be it known that I, EDWARD P. THOMPSON, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in the Method of Evacuating Incandescent Electric Lamps, of which the following is a specification.

The invention relates to a process of increasing the vacuums obtained in incandescent electric-lamp globes.

The object of the invention is to provide means for assisting the operation of the vacuum-pump in exhausting the atmosphere.

In general terms, the invention consists in causing during the operation of the pump successive explosions or displacements of the contained atmosphere by means of electrical discharges occurring within the evacuatingchambers.

The accompanying drawingillustrates a general organization of apparatus adapted to carry out the invention.

Referring to the figure, A represents a vacuum-pump of any suitable character, and Ba vacuum chamber connected therewith. In this instance a series of electric lamps, b b, are connected with the chamber, and these may, if desired, be placed in an electric circuit, L L. The pump is operated in the usual manner for exhausting the atmosphere, and at the proper stage the action of the pump is assisted by securing successive electrical discharges within the chamber B. This is conveniently accomplished by placing two discharge-balls, e and e, at points sufliciently removed within the chamber B. These are connected with any suitable source of electricity, E, capable of producing a current which will pass through the attenuated atmosphere in the chamber B.

It is well known that a certain displacement of the atmosphere is caused by the discharge of an electric current or spark, and the pump, acting during this time, serves to carry off a greater portion of the atmosphere contained within the chamber than would otherwise be possible. For the purpose of still further increasing the efl'ectiveness of the pump, the filaments of the lamps may be raised to greater (No model.)

or less incandescence by passing currents through them during the process of evacuating, they being connected with the conductors L L.

I am aware that it is not new to pass a current of electricity through the exhaustingchamber of a vacuum apparatus for the purpose of determining the degree of vacuum; but such process is employed, not in connection with the process of evacuating, but merely to determine the degree of the vacuum. Moreover, in this process of determining'the degree of vacuum a silent discharge is necessary in order to obtain the color upon which the usefulness of the process depends, whereas in the present invention a disruptive discharge is necessary to secure the desired result. By using the balls 6' and e the discharges will be disruptive. In certain other applications of even date herewith, Serial Nos. 225,113 and 225,115, there are described methods and apparatus for producing high vacuums, in some respects resembling that described herein.

I claim as my invention- 1. The hereinbefore-descrihed process of evacuating electriclamp globes, which consists in exhausting the atmosphere, by a vac uum-pump and simultaneously causing electric sparks to discharge through the vacuumehamber. 8o

2. The hereinbefore-described process of increasing vacuums, which consists in mechanically attenuating the atmosphere, and in simultaneously causing momentary increase of pressure by causing successive electrical discharges within the atmosphere and withdrawing a portion of the atmosphere by reason of such increase of pressure.

3. In an apparatus for producing vacuums, the combination, with a vacuum-pump and a chamber connected therewith, of dischargeballs within such chamber and means for charging the same electrically, substantially as described.

y 4. The hereinbeforedescribed process of in creasing vacuums, which consists in mechanically attenuating the atmosphere, and in simultaneously causing momentary increase of pressure by causing successive electrical dis charges within the atmosphere and withdraw rec ing a portion of the atmosphere by reason of chamber, and heating the atmosphere by rais- IO such increase of pressure, and by independing the filaments to ineandescenee. ent means increasing the temperature of the In testimony whereof I have hereunto subatmosphere. scribed my name this 19th day of January, A.

5. The hereinbefore-deseribed process of I D. 1887.

evacuating electric-lamp globes, which con- EDWARD P. THOMPSON.

sists in simultaneously exhausting the atmos- Witnesses: phere by a Vacuum-pump, causing electric DANL. W. EDGEOOMB, sparks to discharge through the vacuum, CHARLES A. TERRY. 

